Method for producing lactic acid from glycerin catalyzed by a supported copper catalyst

Abstract

The invention relates to the technical field of lactic acid preparation, in particular to a method for preparing lactic acid from glycerin catalyzed by a supported copper catalyst. The selectivity of lactic acid can reach 70-90%, and the conversion rate of glycerin can reach 72-100%. It is characterized in that: glycerin is used as raw material, and supported copper oxide is used as catalyst, and under the alkaline conditions provided by an alkali source in the absence of oxygen, the reaction is carried out in a high-pressure reactor to obtain lactic acid, and the supported copper oxide catalyst is The carrier is metal oxide including MgO, ZrO2, TiO2, CeO2 and ZnO, active carbon or hydroxyapatite. The supported copper catalyst is easy to prepare, low in price and long in service life. The invention has the advantages of low reaction temperature and pressure, high catalyst activity and good selectivity, fast reaction rate, safe and environment-friendly process, etc., and has good industrial prospect.

Description

technical field [0001] The invention relates to the technical field of lactic acid preparation, in particular to a method for preparing lactic acid from glycerin catalyzed by a supported copper catalyst. Background technique [0002] Lactic acid, chemical system name 2-hydroxypropanoic acid (2-Hydroxypropanoic Acid), because the carbon atom at the α position of the carboxyl group in the lactic acid molecule is an asymmetric carbon atom, so lactic acid has two kinds of optical activity: left-handed (L-type) and right-handed (Type D) enantiomer; lactic acid was first discovered in yoghurt by Scheele in 1850, hence the name of lactic acid; lactic acid is one of the three recognized organic acids in the world, and widely exists in the human body, animals and microorganisms Metabolism also exists in every aspect of people's life. [0003] Lactic acid is an organic acid with a wide range of uses, mainly used in the food and pharmaceutical industries. In the brewing industry, lact...

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Problems solved by technology

[0004] Glycerol is a by-product of the biodiesel production process. For every ten tons of biodiesel produced, one ton of glycerin is produced. With the increase of biodiesel production year by year, the production of glycerin is also very large. A series of chemicals are produced by converting glycerin As well as chemical intermediates, it has the characteristics of renewable and zero carbon dioxide emissions, and glycerin is rich in active hydroxyl groups, which can be easily replaced to synthesize specialty chemicals. Therefore, the development and utilization of glycerin has great prospects; recent studies have found that the use of glycerin to prepare lactic acid Not only has the new use of glycerin been developed, it has also provided a sustainable source of raw materials for lactic acid; it can be known from literature reports that there are fermentation methods and chemical synthesis methods for the preparation of lactic acid from glycerin, and the chemical synthesis methods include noble metal aerobic catalysis and high-temperature hydrothermal anaerobic Oxidation method; while the fermentation method and noble metal aerobic catalysis method have the disadvantages of high cost, low glycerin reaction concentration and long reaction time; high temperature hydrothermal anaerobic oxidation method requires high reaction temperature and reaction pressure; DebdutRoy et al. adopt industrial production Cu / SiO 2 , CuO / Al 2 o 3 and Cu 2 O, can effectively reduce the reaction temperature, but the reaction temperature, reaction time and lactic acid selectivity need to be improved